Valve for methane in automotive systems with improved sealing

ABSTRACT

A valve ( 1 ) controls flow of methane in automotive systems and includes at least one sealing group ( 98 ) having a proximal sealing ring ( 99   a ), in direct contact with the gas in rest conditions. A distal sealing ring ( 99 b) is made of different materials. A check valve device ( 120 ) is applicable to the valve ( 1 ) and includes an entrance sealing group ( 130 ) provided with a proximal sealing ring ( 130   a ) and a distal sealing ring ( 130   b ) made of different materials.

The object of the present invention a valve applicable to a reservoir, usually on board a vehicle, for flow controlling of methane gas in automotive systems.

As is known, such valves are provided both with the components for carrying out the usual valve functions of supply of methane to the reservoir and of delivery of the methane to the vehicle engine, and with numerous accessory devices which for example carry out safety functions.

Currently, in the field of valves for methane, the need is felt to have valves that can control very large reservoirs, such as intended for commercial vehicles, industrial vehicles and the like.

For such valves, special technical solutions are required, which for example allow a refill of the reservoir at high speed.

In particular, among the many consequences of carrying out a supply at high speed, there is the considerable lowering of the temperature of the valve, due to contact with the flow of gas being supplied. Some experimental data show, for example, that the flow of incoming gas at high speed reaches a temperature of even −50° C. or less for short time intervals.

At such temperatures, traditional seals provided in the valve show some drawbacks that impair the optimal performance thereof, with the consequent risk of a gas leaks during refueling.

The object of the present invention is to provide a valve for methane which meets the above requirements and overcomes the drawbacks of the prior art.

Such an object is achieved by a valve for methane made according to claim 1. The dependent claims describe embodiment variations.

The features and advantages of the valve or methane according to the present invention will appear more clearly from the following description, made by way of an indicative and non-limiting example with reference to the accompanying figures, in which:

FIG. 1 shows a valve for methane according to an embodiment of the present invention, according to a first observation point;

FIG. 2 shows the valve in FIG. 1, according to a further observation point;

FIG. 3 shows a plan view of the valve in FIG. 2;

FIG. 4 shows a sectional view of the valve in FIG. 2, according to the sectional plane IV-IV in FIG. 3;

FIG. 5 shows a sectional view of the valve in FIG. 2, according to the sectional plane V-V in FIG. 3;

FIG. 6 shows a detail of a check valve device of the valve according to the present invention;

FIG. 7 shows a detail of a tap of the valve according to the present invention;

FIG. 8a shows a detail of the thermal safety device of the valve according to the present invention, in a closed configuration;

FIG. 8b shows a detail of the thermal safety device of the valve according to the present invention, in a final open configuration; and

FIG. 9 shows a detail of a portion of electrovalve of the valve according, to the present invention.

With reference to the accompanying figures, reference numeral 1 globally denotes a valve applicable to a reservoir (not shown) for controlling the flow of methane in automotive systems. Usually, the reservoir is installed on board a vehicle and the methane therein is stored at high pressure. The valve is permanently applied to the mouth of such a reservoir, except in case of extraordinary maintenance.

Valve 1 comprises a valve body 2, preferably made in one piece, for example of a metal material such as brass, aluminium and the like.

The valve body 2 comprises in particular a neck 4, preferably threaded, for example externally, for screwing with the mouth of the reservoir, and a reservoir duct 6 made through neck 4, for the transit of methane into the internal chamber of the reservoir in a filling step of the reservoir and from the reservoir in an emptying step, in case of intervention of a safety device.

Preferably, the reservoir duct 6 extends along a rectilinear attachment axis Z and ends in a plurality of main apertures 8, for example shaped as windows that follow one another circumferentially, placed through the side wall of neck 4, for the transit of the gas.

Moreover, the valve body 2 comprises an entrance duct 10, annularly delimited by a lateral entrance wall 10 a, which extends along a rectilinear entrance axis X, for the entry of methane during refueling.

In particular, the entrance duct 10 is adapted for connection with a charging pipe, upstream of which the user can insert the filler to supply the methane.

Valve 1 comprises a check valve device 120, applied to the entrance duct 10, at least partially housed in said entrance duct 10.

The check valve device 120 preferably comprises a tubular main body 122, which extends between a front end 124, external to the valve body 2, and an opposite rear end 126. At the front end 124 there is an entrance aperture 128 for the connection with the charging pipe.

The main body 122 is applied to the entrance duct 10, for example by means of an outer thread 125.

Axially alongside the outer thread 125, on the side facing the interior of the valve body 122, device 120 is provided with an entrance sealing group 130 with the lateral wall 10 a of the entrance duct 10.

The entrance sealing group 130 comprises at least a pair of entrance sealing seats, and in particular a proximal sealing seat 130 a and a distal sealing seat 130 b, with reference to the rear end 126 of the main body 122.

Moreover, the entrance sealing group 130 comprises an entrance sealing ring housed in the respective entrance sealing seat; in particular, the entrance sealing group 130 includes a proximal sealing ring 132 a, arranged in the proximal sealing seat 130 a, and a distal sealing ring 132 b, arranged in the distal sealing seat 130 b.

The proximal sealing ring, i.e. the innermost ring in the valve body, in direct contact with the gas in rest conditions, and the distal sealing ring, i.e. the outermost ring in the valve body, are made of different materials in order to achieve the optimum seal in different or only partially overlapping temperature ranges.

In particular, the material of the distal sealing ring has at low temperatures, for example in the range of −30° C.-50° C., an elasticity greater than the material of the proximal sealing ring.

Moreover, the material of the distal sealing ring is adapted to achieve an optimum seal even at very low temperatures, such as −70° C., even if for short periods of time.

The material of the distal sealing ring also ensures a methane seal, good hardness and thus mechanical resistance to pressure at such temperatures.

For example, according to an embodiment of the invention, the proximal sealing ring 132 a of the entrance sealing group 130 is made of fluorocarbon rubber, for example an FKM fluorocarbon rubber.

On the other hand, the distal sealing ring 132 b of the entrance sealing group 130 is for example made of a fluorosilicone rubber, such as an FMQ or an FVMQ rubber, which maintains excellent sealing properties even at low temperatures.

In other words, the proximal sealing ring is made of an effective and functional material for sealing at temperatures between +200° C. and −20° C. (or with special mixtures up to −40° C.) and the distal sealing ring is made of an effective and functional material for sealing at lower temperatures, such as between +170° C. and −50° C. (and even lower, such as −70° C. for short time intervals).

According to a preferred embodiment, the entrance sealing group 130 includes at least one anti-extrusion ring arranged in the relative sealing seat together with the respective sealing ring, adapted to prevent the escape of the sealing ring from its seat.

For example, the entrance sealing group 130 includes an anti-extrusion ring 134, arranged in the distal sealing seat 130 b together with the relative distal sealing ring 132 b.

For example, the anti-extrusion ring is made of polytetrafluoroethylene (PTFE).

The valve device 120 includes an obturator group 140, housed in the main body 122, including a check obturator 142 adapted to translate to allow or prevent the transit of gas through the main body 122.

Preferably, moreover, the valve body 2 comprises an auxiliary reservoir duct 14 intended to be connected to a further reservoir to increase the autonomy of the vehicle.

Preferably, the auxiliary reservoir duct 14 extends along an auxiliary attachment axis K, for example coaxial with the entrance axis X.

Moreover, the valve body 2 includes a delivery duct adapted to be connected with the vehicle engine to supply it with methane.

Preferably, the delivery duct 20 extends along a rectilinear delivery axis Y, for example distinct from and parallel to the entrance axis X and, if provided, to the auxiliary reservoir axis K.

Valve 1 further comprises a feed duct 30 connected upstream with the internal chamber of the reservoir and downstream with the delivery duct 20, fluidically separate from the reservoir duct 6.

In particular, the feed duct 30 comprises a by-pass duct 32, placed within the reservoir duct 6, separate from said reservoir duct 6; for example, the by-pass duct is defined by a by-pass tube 34 housed in the reservoir duct 6.

The feed duct 30 further comprises, preferably, an auxiliary passage 36 made in the valve body 2, connectable upstream with the by-pass duct 32 and connectable downstream with the delivery duct 20.

Preferably, between the by-pass duct 32 of the feed duct 30 and the auxiliary passage 36, the valve body 2 has a closure seat 38 and, a valve seat 40 between the auxiliary passage 36 and the delivery duct 20.

Preferably, valve 1 comprises a manual tap 50, applied to the valve body 2, adapted to be manipulated to engage an obturator body 152 with the closure seat 38 to obstruct, in whole or in part, the transit of the methane from the by-pass duct 32 to the auxiliary passage 36 (and thus to the delivery duct 20).

The manual closing operation is necessary to perform maintenance operations downstream of valve 1.

In normal operation, tap 50 is clearly open and the transit of methane from the by-pass conduit 32 to the auxiliary passage 36 is free.

According to a preferred embodiment, tap 50 includes a knob 154, located outside the valve body 2, rotatable about a tap axis D, such as parallel or coincident with the attachment axis Z of the reservoir duct 6.

Tap 50 also includes a shaft 156, integral with the knob and engaged with obturator 152 to cause the lowering (and thus the closure) or lifting (and thus the opening) thereof by the closure seat 38.

Preferably, tap 50 also includes, between shaft 156 and the valve body 2, a fixed bush 158, crossed by shaft 156 before engaging with obturator 152.

According to an embodiment of the invention, shaft 156 of tap 50 includes a first tap sealing group 160 which produces a gas seal between shaft 156 and bush 158 (or, in an embodiment variation not shown, with the surrounding wall of the valve body 2).

The first tap sealing group 160 includes a proximal seat 160 a, towards the inside of the valve body, and a distal seat 160 b as well as respective sealing rings 162 a, 162 b, housed in the respective seats and, preferably, an anti-extrusion ring 166.

As shown with reference to the entrance sealing group 130, also for the first tap sealing group 160 the proximal sealing ring, i.e. the innermost ring in the valve body, in direct contact with the gas in rest conditions, and the distal sealing ring, i.e. the outermost ring in the valve body, are made of different materials in order to obtain an optimal seal in different or only partially overlapping temperature ranges.

According to one embodiment of the invention, bush 158 of tap 50 includes a second tap sealing group 170, which forms a gas seal between the valve body 2 and bush 158.

The second tap sealing group 170 includes a proximal seat 170 a,towards the interior of the valve body, and a distal seat 170 b, as well as respective sealing rings 172 a, 172 b, received in the respective locations and, preferably, an anti-extrusion ring 176.

As shown with reference to the entrance sealing group 130, also for the second tap sealing group 170 the proximal sealing ring, i.e. the innermost ring in the valve body, in direct contact with the gas in rest conditions, and the distal sealing ring, i.e. the outermost ring in the valve body, are made of different materials in order to obtain an optimal seal in different or only partially overlapping temperature ranges.

Moreover, valve 1 includes an electrovalve 60, applied to the valve body, adapted to be operated remotely, electronically, to allow or prevent the methane flow to the delivery duct 20, for example depending on the on or off condition of the engine, or more generally on the controls from the vehicle electronic control unit.

To this end, an obturator body 62 of electrovalve 60 cooperates with the valve seat 40 to prevent the methane flow to the delivery duct 20.

Preferably, electrovalve 60 includes an engagement body 64, for example screwed to the valve body by a threading 66, within which the obturator member 62 of said electrovalve 60 is supported in a translatable manner.

According to an embodiment of the invention, the engagement body 64 of electrovalve 60 comprises an electrovalve sealing group 180 which forms a gas seal between the engagement body 64 and the valve body 2.

The electrovalve sealing group 180 comprises a proximal seat 180 a, towards the interior of the valve body, and a distal seat 180 b, as well as respective sealing rings 182 a, 182 b, housed in the respective seats and, preferably, an anti-extrusion ring 186, for example arranged in the proximal seat 180, in engagement with the proximal ring 182 a.

Preferably, thread 66 is placed between the proximal seat 180 a and the distal seat 180 b.

As shown with reference to the entrance sealing group 130, also for the electrovalve sealing group 180 the proximal sealing ring, i.e. the innermost ring in the valve body, in direct contact with the gas in rest conditions, and the distal sealing ring, i.e. the outermost ring in the valve body, are made of different materials in order to obtain an optimal seal in different or only partially overlapping temperature ranges.

Valve 1 further includes an excess flow blocking device 70 operating upstream of the feed duct 30, and in particular upstream of the by-pass duct 32 thereof, and downstream of the main aperture 8 of the reservoir duct 6 towards the internal chamber of the reservoir.

The blocking device 70 is adapted to choke the transit of methane to the feed duct 30 in the presence of a methane flow exceeding a predefined threshold value.

For example, such a blocking device 70 is actuated when, due to a rupture of a tube downstream of the delivery duct 20, there is an increased methane flow that escapes.

Moreover, the valve body 2 includes a discharge duct in communication downstream with the external environment and connectable upstream with the reservoir duct 6 and, in the variants provided with the auxiliary reservoir duct 14, with said auxiliary reservoir duct 14.

The discharge duct 80 extends along a rectilinear discharge axis Y.

According to the invention, valve 1 further comprises a temperature-sensitive thermal safety device operating between the reservoir duct 6 and the discharge duct 80 and adapted, in a closed configuration, to prevent the transit of methane from the reservoir duct 6 to the discharge duct 80 and in an open configuration, to allow the transit of methane from the reservoir duct 6 to the discharge duct 80.

The thermal safety device 90 is adapted allow the discharge of methane from the reservoir duct 6 to the discharge duct 80 (i.e. towards the external environment) when the temperature exceeds a predefined threshold value and prevent such a discharge.

According to a preferred embodiment, the valve body includes a safety chamber 92 in communication on one end with the reservoir duct 6 (and with the auxiliary reservoir duct 14, if provided), via a safety aperture 92 a; on the other end, the valve body includes a rear compartment 93, closed by a plug 94, for example threaded.

Preferably, the safety chamber 92 extends along a safety chamber axis A, preferably perpendicular to the attachment axis Z of the reservoir duct 6.

Preferably, moreover, the safety chamber axis A is perpendicular to the discharge axis W of the discharge duct 80.

The safety chamber 92 is connectable with the discharge duct 80 and also has an abutment 92 b, placed for example between the safety aperture 92 a and the discharge duct 80.

The thermal safety device 90 comprises a main obturator 96, sealingly sliding in the safety chamber 92 and adapted, through a radial projection 96 a thereof, to abut with abutment 92 b, defining the advance end stroke.

For example, the main obturator 96 includes a front sealing group 98, for the seal between the safety chamber 92 and the discharge duct 80, and/or a rear sealing group 102, for the seal between the rear compartment 93 and the discharge duct 80.

Preferably, the section on which the front sealing group 98 operates is less than the section on which the rear sealing group 102 operates.

According to an embodiment of the invention, the front sealing group 98 includes a proximal seat 98 a, close to the safety chamber 92, and a distal seat 98 b, as well as a proximal sealing ring 99 a housed in the proximal sealing seat 98 a and a distal sealing ring 99 b housed in the distal sealing seat 98 b, and, preferably, an anti-extrusion ring 100 housed in the distal seat 98 b.

Likewise, the rear sealing group 102 includes a proximal seat 102 a, close to the rear compartment 93, and a distal seat 102 b, as well as a proximal sealing ring 103 a housed in the proximal sealing seat 102 a and a distal sealing ring 103 b housed in the distal sealing seat 102 b and, preferably, an anti-extrusion ring 104 housed in the distal seat 102 b.

As shown with reference to the entrance sealing group 130, also for the front sealing group 98 and for the rear sealing group 102 the proximal sealing ring, i.e. the innermost ring in the valve body, in direct contact with the gas in rest conditions, and the distal sealing ring, i.e. the outermost ring in the valve body, are made of different materials in order to obtain an optimal seal in different or only partially overlapping temperature ranges.

The main obturator 96 has a through duct 106, which connects the area upstream of obturator 96 with the downstream area, i.e. with the rear compartment 93.

In particular, the through duct 106 is in connection with the rear compartment 93 through an orifice 108 smaller than the passage section of the remaining part of the through duct 106.

The safety device 90 further comprises an elastic safety element 110, adapted to influence in closing, for example, to push in closing, the main obturator 96, towards the advance stroke end abutment 92 b.

For example; the elastic safety element 110 is in compression between plug 94 and the main obturator 96.

The thermal safety device 90 further comprises a temperature-sensitive driving device 220 adapted to influence the main obturator 96 to move it and put the reservoir duct 6 in communication with the external environment through the discharge duct 80.

In particular, the driving device 220 is sensitive to the external temperature and adapted to generate a pressure differential between the area upstream of the main obturator 96 and the area downstream of the same, i.e. the rear compartment 93, in order to obtain the movement of said main obturator 96 and put the reservoir duct 6 in communication with the discharge duct 80.

According to a preferred embodiment, the driving device 220 comprises a driving obturator 222, sliding in a driving seat 224.

Preferably, the driving seat 224 extends along a driving seat axis B, for example incident, for example orthogonally, to the safety chamber axis A.

Preferably, the driving seat 224 has a section smaller than the section of the safety chamber 92 in which the main obturator 96 slides and that connects the reservoir duct 6 with the discharge duct 80.

The driving obturator 222 comprises a driving sealing group 225 for the seal with the driving seat 224.

According to an embodiment of the invention, the driving sealing group 225 includes a proximal seat 225 a, next to the rear compartment 93, and a distal seat 225 b, as well as a proximal sealing ring 226 a housed in the proximal sealing seat 225 a and a distal sealing ring 226 b housed in the distal sealing seat 225 b and, preferably, an anti-extrusion ring 227 housed in the distal seat 225 b.

As shown with reference to the entrance sealing group 130, also for the driving sealing group 180 the proximal sealing ring, i.e. the innermost ring in the valve body, in direct contact with the gas in rest conditions, and the distal sealing ring, i.e. the outermost ring in the valve body, are made of different materials in order to obtain an optimal seal in different or only partially overlapping temperature ranges.

The valve body 2 also has a driving compartment 228 connected upstream with the downstream area of the main obturator 96 or the rear compartment 93 and downstream with the external environment.

For example, the driving compartment 228 is in connection with the external environment via a driving duct 229, for example made in the valve body 2, which connects it with the discharge duct 80.

Preferably, the driving obturator 222 is adapted to close the connection between the driving compartment 228 and the area downstream of the main obturator 96 or the rear compartment 93, through the driving sealing group 225.

Preferably, the driving device 220 comprises an elastic driving element 232 adapted to influence in opening the driving obturator 222, i.e. in the direction of moving said driving obturator 222 to put the area downstream of the main obturator 96 or rear compartment in communication with the external environment, for example through the driving compartment 228.

The safety device 90 further comprises a thermosensitive element 240 sensitive to temperature which, for a temperature higher than a predefined threshold becomes yielding to the mechanical actions exerted by the driving obturator 222; for example, said thermosensitive element 240 melts or bursts or becomes so soft as not to oppose said mechanical actions.

The thermosensitive element 240 is arranged to oppose the opening movement of the driving obturator 122; for example, the thermosensitive element 240 is in abutment with the driving obturator 222 on one end and in abutment with a fixed element 242, for example a bottom of a plug 244, on the other.

Preferably, the thermosensitive element 240 is housed in an auxiliary compartment 246, delimited by said bottom 242 and by the driving obturator 222.

Preferably, the auxiliary compartment 246 is in communication with the external environment through holes 246 a (FIGS. 1 and 2) formed through bottom 242 of plug 244. The driving obturator 222 also creates a seal with the walls of said auxiliary compartment 246 to prevent the escape of methane through holes. 246 a during the activation step of the thermal safety device.

Preferably, also plug 94 which closes the rear compartment 93 comprises a plug sealing group 300 to provide the seal with the surrounding wall of the valve body 2.

The plug sealing group 300 includes a proximal seat 302 a, close to the rear compartment 93, and a distal seat 302 b, as well as a proximal sealing ring 304 a housed in the proximal sealing seat 302 a and a distal sealing ring 304 b housed in the distal sealing seat 302 b, and, preferably, an anti-extrusion ring 306 housed in the distal seat 302 b.

As shown with reference to the entrance sealing group 130, also for the plug sealing group 180 the proximal sealing ring, i.e. the innermost ring in the valve body, in direct contact with the gas in rest conditions, and the distal sealing ring, i.e. the outermost ring in the valve body, are made of different materials in order to obtain an optimal seal in different or only partially overlapping temperature ranges.

Innovatively, the valve according to the present invention allows maintaining a high reliability of the seals while particularly low temperatures are achieved, for example during refueling.

It is clear that a man skilled in the art may make changes to the valve described above in order to meet incidental needs, all falling within the scope of protection defined in the following claims. 

1. Valve for flow control of methane in automotive systems during supply at high speed and low temperatures, the valve comprising at least one sealing group comprising a proximal sealing seat and a distal sealing seat adjacent to the proximal sealing seat, a proximal sealing ring, in direct contact with gas in rest conditions and housed in the proximal sealing seat, and a distal sealing ring housed in the distal sealing seat, wherein the proximal sealing ring and the distal sealing ring are made of different materials and the material of the distal sealing ring has at the low temperatures an elasticity greater than the material of the proximal sealing ring.
 2. Valve according to claim 1, wherein the material of the distal sealing ring exhibits from −30° C. to −50° C. a greater elasticity than the material of the proximal sealing ring.
 3. Valve according to claim 1, wherein the distal sealing ring is made of an FKM fluorocarbon rubber.
 4. Valve according to claim 1, wherein the distal sealing ring is made of an FMQ or FVMQ fluorosilicone rubber.
 5. Valve according to claim 1, wherein the sealing group comprises at least one anti-extrusion ring housed in a sealing seat to keep the relative sealing ring in sealing seat.
 6. Valve according to claim 5, wherein the anti-extrusion ring is housed in the distal sealing seat to keep the relative distal sealing ring in the distal sealing seat.
 7. Valve according to claim 1, comprising a check valve device applied to an entrance duct, wherein said device comprises said sealing group.
 8. Valve according to claim 1, comprising a tap manually operable to intercept flow of gas towards a delivery duct, wherein said tap comprises a shaft and a bush crossed by said shaft, applied to the valve body.
 9. Valve according to claim 8, wherein the shaft comprises said sealing group to form a seal with the bush.
 10. Valve according to claim 8, wherein the bush comprises said sealing group to form the seal with the valve body.
 11. Valve according to claim 1, comprising a temperature-sensitive thermal safety device comprising an obturator adapted to intercept flow of gas towards a discharge duct, wherein said obturator comprises said sealing group.
 12. Valve according to claim 11, wherein the thermal safety device comprises a driver device adapted to obtain a pressure difference between a zone upstream and a zone downstream of the obturator, wherein said driver device comprises a driving obturator provided with said sealing group.
 13. Valve according to claim 1, comprising a plug for closure of a rear compartment towards outside, wherein said plug is provided with said sealing group.
 14. Valve according to claim 1, comprising an electrovalve to allow or prevent flow of methane towards the delivery duct, comprising an engagement body applied to the valve body and an obturator member, wherein said engagement body comprises said sealing group to form a seal with the valve body.
 15. Check valve device applicable to a valve body of a valve for flow control of methane in automotive systems, said device being adapted to intercept flow of gas between an entrance duct and a reservoir duct of said valve, comprising an entrance sealing group comprising a proximal sealing seat and a distal sealing seat adjacent to the proximal sealing seat, a proximal sealing ring housed in the proximal sealing seat, and a distal sealing ring housed in the distal sealing seat, wherein the proximal sealing ring and the distal sealing ring are made of different materials. 